Science fiction buffs have come up with many strange depictions of alien life, but imagine a creature with a beak like a parrot, no bones in its body, swallows its food through the hole in the centre of its doughnut shaped brain, has three hearts, blue blood, skin that can change colours like a television screen, eight arms growing out of its lips, moves by jet propulsion and can transform its body shape to mimic other life forms. This is no science fiction. It's known as a Cephalopod, or more commonly, an Octopus.

Scientist, author and film-maker, Mark Norman is one of the world's leading experts on octopus, squid, and cuttlefish (Cephalopods) and he takes us night diving in Melbourne's Port Phillip Bay looking for these alien creatures. In this eerie underwater world we discover their strange and elusive behaviours, why they are so rarely seen and why, until recently, we knew so little about them. We examine the body of a Giant Squid, a mythical creature that has never been seen alive in its natural habitat, over a kilometre below the surface of the ocean. And, we put this dedicated scientist and lover of Cephalopods to the ultimate test. Will he eat calamari rings?

Narration: We’re on the outskirts of Melbourne. There’ve been reports that alien life forms have been spotted right at the end of this pier and apparently they only come out at night. Now these scientists know what to expect, they’ve seen these kind of things before. They’re pretty sure what we’re dealing with are Cephalopods. So, do you think they’re down there?...That’s what we’re here to find out. Dr Mark Norman has dedicated his adult life to hunting Cephalopods…. And no… They are not from out of space.

But there is something very science fiction about descending into the icy black waters of Port Phillip Bay in search of the strangest creatures on earth. They’re the ultimate ‘Masters of Disguise’… Almost impossible to find. And as Mark tells it they are so different in design they might as well be aliens.

Mark Norman: You couldn’t get an animal that’s sort of more different or more alien to us. They’ve got such a weird shape to start with. Like they’ve got eight arms coming off their mouth. When they walk around it’s like they’re running round on super lips. They’ve got a head in the middle of their body. They’ve got a doughnut shaped brain. They’ve got three hearts. Blue blood. Jet propulsion. A bag out the back like a beanbag that they stick all the body bits in.

Narration: The Cephalopods include octopus, cuttlefish and squid. This one’s a Southern Sand Octopus. Apart from eating them with fish and chips, most of us know very little about them.

Mark Norman: And I bet most people around here, I mean this is almost the suburbs, they wouldn’t even know these animals are here. I think they’re kind of the ‘monsters of the deep’ …and most people wouldn’t even stick their head under water at night let alone poke around far out in the bay. There are just such amazing creatures out there.

Narration: By diving at night Mark has been able to identify and film the behaviour of these mainly nocturnal animals. One of his particular favourites is the aptly named…Dumpling Squid. He’s not much to look at, but this little guy’s got a few tricks up his tentacles.

Mark Norman: Well one of them is that they can glue sand on the back of their body and have it as camouflage when they’re swimming around during the day. They have special glue glands in their skin and if they get attacked they’ve also got acid glands in the skin and they can squirt acid and that disconnects the glue and the sand coat and they can drop that as a decoy while they swim off in another direction. So they sort of have their own glue and their own anti-glue built into their skin above these nasties that are waiting to chomp any passing shadow.

Jonica Newby: Tell me. Night dives, men in black, do you ever feel like you’re living in an episode of the X Files?

Mark Norman: No. Most of the time we’re sitting going what the hell are we doing here it’s four in the morning, it’s eight degrees in the air, it’s two degrees in the water. We wish we were at home watching the X Files.

Narration: I’m still not convinced. Especially when Mark takes me to his work the next day at the Melbourne Museum. Row upon row of weird life forms preserved in glass jars. They give little indication as to the disguise strategies these animals have when they are alive.

Mark Norman: Well this one is called the day octopus and it’s rare for an octopus to be walking around during daytime and this guy does it because he’s so good at camouflage and so he doesn’t look much while he’s dead, he’s sort of just a big gooby bit of rubber or chewing gum, but when they’re alive the skin of these animals is spectacular. It can do colour changes all the time. It can also do shape changes where it sticks up all these spikes on the body. It can look like seaweeds, can look like rocks, can look like coral and so it’s almost like their skin’s covered in television screens for colour change and then add the shape change on top of it. It makes animation graphics in movies look like paint drying.

Narration: And isn’t he the reason why you nearly didn’t get your Phd?

Mark Norman: The start of my Phd was really bad because I spent three months on my first trip to the Great Barrier Reef looking for octopuses and in three months didn’t find a single octopus. I ended up buying one at a fishing co-op and bringing it home in the boot of my little rusty car thinking my life was over and it wasn’t till the second trip …that I started getting an eye in and getting a feel for the shape of the animals…and what you look for is not a shape because the shape looks like a rock or a coral, you look for a slow movement or a kind of gradual shift in colour out of the corner of your eyes often. And in the early trips I was probably kicking them in the head on a regular basis.

Narration: Since this less than spectacular start Dr Norman has discovered a previously unknown galaxy of cephalopods. He has single-handedly identified over 150 new species. But none so extraordinary as the never before filmed Mimic Octopus.

Mark Norman: Well the mimic octopus is an interesting animal because it takes it one step further. Instead of matching a background like camouflage it actually becomes an object or an animal in its own right and the place that it lives is bare sand flats and mud flats out in shallow waters of Indonesia and New Guinea. And so being caught in the open by a passing fish you’ve got to look either deadly or inedible and this octopus has developed this repertoire of looking like a flounder, poisonous flounder, poisonous lion fish, a poisonous sea snake. It just is able to do all these weird postures and weird behaviours. So in the case of the sea snake if it gets hassled by certain sorts of attackers and it’s often little aggressive damsel fish it will put six arms down a hole, put the other two up and undulate them like the kind of striking pose of a banded sea snake which are very poisonous and are found in the area. So evolution has sort of led to this amazing octopus behaviour where it’s wandering round copying all these things that live in the same area.

Narration: Why do they need such incredibly diverse strategies?

Mark Norman: Well I think the reason that this group’s ended up with such weird forms, high speed, mega camouflage, all these different sorts of behaviours is because they are a really good meal. You don’t have bones. You don’t have armour. You don’t have poisons. You don’t have spines. And so these critters are really rump steak swimming around and so they have to be faster or cleverer or better at squeezing through tiny holes or really good at hiding or conning animals that they are a poisonous sea snake. And so I think the pressure to out evolve their fish predators has led to this amazing group of animals.

Narration: And perhaps the most amazing of all is the legendary giant squid. No one has ever seen one alive. Only these specimens dragged up in fishing nets betray its existence. It has adopted the ultimate defence, hiding deep in the ocean, beyond the reach even of light.

It lives down in these cold black waters acting as an ambush predator shooting out and grabbing passing fish and squid. I love the idea we know so little about it. It’s never been seen live in its natural environment….. It’s actually a good figurehead for how little we know about the deep sea in general and we know very little. We’ve covered less than 1% of the deep ocean floor and yet if people came from outer space and said what is your most common habitat on earth it would be the deep sea and we know more about what’s under rocks on Mars than we do about what’s in our own deep ocean.

Mark Norman: So this will give you an idea of how big giant squids really are. These are the two feeding tentacles out of a 10 metre long giant squid. So these are the tentacles they shoot out to grab their food with. So this is how they grab the squid and the fish that they eat.

Narration: So how big do these things grow?

Mark Norman: Well this one’s about 10 metres long and the biggest on record is 18 metres so the length of a bus.

Narration: They’re just amazing! But still it’s a hell of a lot of calamari.

Mark Norman: It’s a hell of a lot of calamari and the rings would have been the size of car tyres...

Narration: Alright, the acid test. Can I tempt you?

Mark Norman: Calamari. Yes you can.

Narration: I can’t believe it. I mean after everything you know about how intelligent they are and how versatile how can you actually eat them?

Mark Norman: Compared with all the other seafood that’s out there they’re probably one of the better ones to eat. They grow fast. They’re short lived. They reproduce really well. Compare that with prawns or deep sea fish I’d much rather eat this if I don’t think about it too hard.